He was using a size lg pro shape skim. They are about 54" in length but wider than most surfboards. Its harder to be in position and catch waves for sure, but definitely doable as the video shows!
Popping up isn't the problem so much as paddling fast enough and in the right place. Its harder overall for sure. But doable. Domke was using a normal size L pro shape exile skimboard. He loves that thing.
He has been using his standard skim board for skurfing. Its a size Lg domke pro model. (pro shape, 5/8"). Thats a little big for his weight but he likes it. :)